Recovery of oil and other precious fluids from the ground typically involves the drilling of a borehole to the depth necessary to reach the reservoir or pocket of oil. The drilling equipment is then removed and the borehole is lined with a casing to prevent collapse.
In the past, pumping units have been positioned on the surface adjacent the borehole for vertically reciprocating a string of sucker rods extending to a pump within the borehole. This type of pumping unit requires considerable space on the surface. In addition, the pumping unit must be aligned with the pump within the borehole so that pumping efficiency is not adversely affected and the sucker rod string and pump are not injured by the misalignment.
In many situations, the oil or fluid to be pumped to the surface has a viscosity so high that conventional pumping techniques are not effective. Some efforts have been made to heat oil within a borehole to reduce the viscosity of the oil to permit pumping by conventional techniques. These heating techniques have been independent of the pumping techniques and therefore require additional, complex and expensive equipment.
Therefore, a need has been shown to develop a pumping unit for cost effective and reliable pumping of a fluid which may operate on fluids having a wide range of viscosity.